There is provided an amplifier module which includes a plurality of input terminals; a plurality of amplifier circuits configured to amplify a plurality of input signals which are input from each of the plurality of input terminals and output a plurality of amplified signals; and at least one speaker which is directly connected to at least one output terminals from among the plurality of amplifier circuits, wherein the amplifier module may output the plurality of amplified signals to the at least one speaker based on a number of the at least one speaker.

An envelope tracking (ET) power management circuit is provided. The ET power management circuit includes an amplifier circuit(s) configured to output a radio frequency (RF) signal at a defined power level corresponding to a direct current, an alternating current, and an ET modulated voltage received by the amplifier circuit(s). The ET power management circuit can operate in a high-power ET mode when the defined power level exceeds a defined power level threshold and the RF signal is modulated to include no more than a defined number of resource blocks. The ET power management includes two ET tracker circuitries each generating a respective ET modulated voltage and two charge pump circuitries each generating a respective current. In the high-power ET mode, both charge pump circuitries are activated to each provide a reduced current to the amplifier circuit, thus helping to reduce a footprint and cost of the ET power management circuit.

Embodiments of circuits for use with an amplifier that includes multiple amplifier paths include a first circuit and a second circuit in parallel with the first circuit. The first circuit includes a first input coupled to a first power divider output, a first output coupled to a first amplifier path of the multiple amplifier paths, and a first adjustable phase shifter and a first attenuator series coupled between the first input and the first output. The second circuit includes a second input coupled to a second power divider output, a second output coupled to a second amplifier path of the multiple amplifier paths, and a second adjustable phase shifter coupled between the second input and the second output.

In some embodiments, a wireless local area network (WLAN) front-end can be implemented on a semiconductor die having a semiconductor substrate, and a power amplifier implemented on the semiconductor substrate and configured for WLAN transmit operation associated with a frequency range. The semiconductor die can further include a low-noise amplifier (LNA) implemented on the semiconductor substrate and configured for WLAN receive operation associated with the frequency range. The semiconductor die can further include a transmit/receive switch implemented on the semiconductor substrate and configured to support the transmit and receive operations.

Radio frequency (RF) filters configured to filter undesired signal components (e.g., noise and harmonics) from RF signals are disclosed. In one embodiment, an RF filter includes a first inductor coil having a first winding and a second inductor coil having a second winding and a third winding. The second winding of the second inductor coil is configured to have a first mutual magnetic coupling with the first winding, while the third winding of the second inductor coil is configured to have a second mutual magnetic coupling with the first winding. The second winding is connected to the third winding such that the first mutual magnetic coupling and the second mutual magnetic coupling are in opposition. In this manner, the first inductor coil and the second inductor coil may be provided in a compact arrangement while providing weak mutual magnetic coupling between the first inductor coil and the second inductor coil.

A radio frequency (RF) power combining amplifier circuit has a circuit input and a circuit output. A first amplifier is connected to the circuit input and to a first bias input. A first output matching network is connected to an output of the first amplifier and to the circuit output. A second amplifier is connected to the circuit input and to a second bias input. A second output matching network is connected to an output of the second amplifier, and to the circuit output. A voltage level of an input signal applied to the circuit input, together with the respective first bias input and the second bias input, selectively activates the first amplifier and the second amplifier.

In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal.

Systems and methods of the disclosed subject matter for converting light into electrical signals are provided including receiving light input and outputting electrical signals proportional to the light input with a sensor, increasing a transimpedance gain of an amplifier to amplify the electrical signals with a T-network of resistors coupled to the amplifier and the sensor, filtering the electrical signals with a filter circuit coupled to the amplifier and the T-network of resistors to increase noise rejection in a predetermined frequency range, and outputting the filtered electrical signals.

A payload subsystem of a satellite includes a plurality of transmit antenna feeds, a plurality of frequency filters, and a power amplification arrangement including a plurality of power amplifiers. The power amplification arrangement has at least one multiport amplifier, the multiport amplifier including a plurality of output ports, each output port coupled with a respective one of the plurality of transmit antenna feeds by way of a respective one of the plurality of frequency filters.

A cascode power cell for a power amplifier circuit includes a radio frequency signal input node, a radio frequency signal output node, and a plurality of sub-cells each including a first transistor having a collector coupled to the radio frequency signal output node, each of the plurality of sub-cells further including a second transistor having a collector coupled to an emitter of the first transistor at a connection node, and a base coupled to the radio frequency signal input node, the connection nodes for each of the plurality of sub-cells being electrically isolated from one another.